Printing telegraphy



E.P.BANCROFT sep1.15,1925. 1 1,553,304

PRINT ING TELEGRAPHY Filed Peo, 31, 1921 2 Sheets-Sheet i f (g 1V,11111 -n//h P54? 6//0/7 y K M ,My

Sept. l5, 1925.y

A E. P. BANCROFT PRINTING TELEGRAPHY efSneets-sheet 2 Fuga Dec.- 31. 1921 lll rr sTATEs istanti PATENT ERWIN P. BANCROFT, OE BROOKLYN, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF lNEN' YORK, N. Y., A CORPORATION OF NEW YORK.

PnrivTING TELEGRAPHY.

Application filed December 31, 1921. Serial No. 526,244.

To all whom t may concern.

Bc it known vthat I, ERwIN P. BANcRoF'r, a citizen of the United States, residing at Brooklyn, in the county of Kings, State of AYew York, have invented certain new and useful Improvements in Printing Telegraphy, of which the following is a full, clear, concise, and exact description.

rl`his invention relatesto telegraph sys-- tems. l

An object of the inventlon is to pro`v1de a system whereby a plurality of telegraph mes-Y sages originating at separate stations may be transmitted over a plurality of branch llnes or extension circuits to'main or central sta= tions where synchronous multiplex apparatus is located for automatically and simultaneously transferring the code oombinatlons transmitted to the extension circuits or' branch lines. A l

The invention provides synchronous multiplex and start-stop apparatus at the central stations with means associated therewith lmultiplex apparatus. Likewise, accordingtoA mitted tothe multiplex apparatus providing, .'thatthe speed of t p A e start-sto apparatus 1s equal toor'sli'ghtly less than t e speed of the oneof the embodiments of the `invent1on there is provided intermediate the synchronous multiplex apparatus associated with the line conductor connecting the two stations and the start-stop apparatus which transmits the impulsesreceived from the synchronous multiplex apparatus to the extension circuit, means such as a group of condensers and relays for providing a complete overlap between the selections received on the multiplex apparatus and those transmitted by lthe start-stop apparatus.

The invention is illustrated in the accom- 'panying drawings which represent one embodiment.. of the invention and when arranged so that Fig. 1 is to the left of Fig. 2, a. complete system is shown diagrammatically. p

The invention, i-n general, comprises a ybranch office/A which is connected with a main or central oliiceB by an extension circuit or branch line 6, a central or main station C connecting with the main station B by a line conductor 7 equipped with duplex apparatus anda distant branch office D Y which, like branch office A, is connected with the associated-central station C by an.

extension circuit .8.

At the brauch office A there are located transmitting and receiving equipments E and'F, respectively, being shown diagram- Y matically. The extension circuit 6 may be a pair of line conductors or a single line conductor equipped with duplex a paratus as illustrated in the drawings.- oth of the central stations B `and C are provided 'with receiving distributors G and H of the startstop type to receive the code combinations of message impulses from the respective substations or branch oices and transfer them to the multiplex synchronous distributors I and also located at the ollices B and C, re-v spectively, through the instrumentalities of a plurality of groups of relays. Also located at the central offices ares nchronousmultiplex distributors K and each of which the line conductor 7 connecting these two stations andltran'sferrin'g the4 same to the start-stop distributors N and R, respectively,

through the instrumentalities of' a series of condensers, and a group of relays which, ac-

cording to. the present invention,l provide` a serve to receivethe signaling impulses from complete overlap between the selections received on the synchronous multiplex distributor` and those transmitted to the extension circuits by the start-stop distributors associated therewith, Branch oflice D like branch otlice A is provided With a transmitting distributor I3 and a receiving distributor Q vvhich serve their respective purposes. F or the sake of simplifying the drawing, the apparatus common to one channel has been shown in detail While that individual to the other channel has been shown schematically.

The transmitting equipment E comprises an intermittently rotary distributor 10 havinga brush arm 11 Which carries a pair of brushes 12 and 13, Which in turn, are arranged to make contact. with rings 14, 15, 16 and 17. The outer Aring 17 is divided into a plurality of segments 18, 19, 20, 2l, 22 and 23 which are connected with-the respective contacts of a transmitter shown diagrammatically at 24. In order that the brush arm 11 will be stopped and released once per revolution, a release magnet 27 is provided which is under the control of a start relay 28 which is controlled by a common contact on the transmitter 24. The transmitter 24 consists of a plurality of movable contacts 30, 31, 32, 33 and 34 Which are connected to the respective segments forming the outer ring 17 of the distributor 10. Also in the transmitter 24 is a common contact 35 which, as previously stated, controls the energization ot the start relay 28. Although the transmitter M has been shown diagrammatically as a keyboard transmitter'anyavell-known type of transmitter may be substituted therefor.

At the central ofiice B there is shown a receiving distributor G of4 the start-stop type and a synchronously operated distributor I which has its continuous ring 95 connectedto the apex of the ratio arms which includes the receiving relay 99 forming a part of the duplex equipment associated with .the line conductor 7. The line relay 99 responds only yto incoming impulses and Eis non-responsive to outgoing impulses. Upon the operation ofv themultiplex distributor I, this relay Will not respond to impulses which may be transfered thereto from the startsto .distributor G.

e start-stop distributor G comprises an outer ring 44 and an inner ring 40. Form ing la part of the outer ring is a plurality of segments 47, 48, 49, 50, 51 and 52, each of `which corresponds to respective ones of the segmentson the transmitting distributor 10. By the proper orientation of these segments and inasmuch as they are smaller than the transmitting segments of the transmitting distributor 10, the central portion ot the slgnaling impulses transmitted over the extension circuit 6 to the line relay 37 will be picked up tor each segment of the .iding face at the branch office A. The distributor G also comprises a brush arm 41 carrying a brush 42 which is held against rotation by a release latch under the control of a release magnet 39.

Interposed between the start-stop dis tributor Gr and the multiplex or synchronously operated distributor I are a plurality ot' groups of storing relays which are operable in accordance with the signals transmitted and controlled by a series ot transtenrclays under the control of both t-he start-stop distributor G and the multiplex I. These sets of relays provide a complete overlap between the selections received from the start-stop distributor G and those transmitted Vover the lin'e.7 by the multiplex distributor I irrespective of what the phase relation is between the brush arm of the start-stop distributor G and the brush arm of the multiplex distributor I providing, of course, that the speed of the brush arm ot the start-stop distributor is equal to or slightly less than the speed of the brush arm ot the multiplex distributor I. The relays 56, 57, 58, 59 and 60 forming the first group ot storing relays are connected directly to the receiving segments forming the outer ring 44 of the distributor G and will be energized in accordance With the operation of relay 38. The second set of storing relays comprises relays 70, 71, 72, 73 and 7 4 which are under the control of the corresponding relays of the first set, the energizing circuits of which are completed-through the right-handarmature of relay 66, which, as more clearly described hereinafter, is

Vcontrolled through contacts of the relay 61 has been transmitted from the distributor G to the first set of storing relays, the transfer relay 65 is energized under the joint con- A trol of the start-stop distributor G and the multiplex distributor I for transferring the impulses stored on the first set to the relays forming the second set. Accordingly, the third set of storing relays Will be energized depending upon the energization of the re-. ylays of the vsecond set.

All of the relays will be locked up through their own contacts folloyving their initial energization so that' after once being energized aremaintained energized independent of the impulses coming in on the extension circuit 6. After the impulsesstored in the first set of storing relays have been cleared out the next succeeding message impulses may be stored in the storing relays 56to 60, inclusive. After the secondl set of storing relays 70 to, 74, inelu- I sive, are 'energized they establish through their contacts, energizing circuits; for the corresponding ones of the storing relays of the third set, Which, like the second set, are locked up and retained in such ,position until released byxa relay unde'r the Ycontrol of the multiplex distributor I. It is through' the contacts of the third set of storing relays that the polarity ofthe impulses "corresponding to the various characters is varied.

In order that'the impulses will bev transferred from the respective parts yof the circuit so that no mutilation of the signalswill result, such transfer is under the oint control of the start-stop distributor 't landsthe synchronous multiplex distributor I, as will be more clearly described hereinafter.

rIlhe apparatus -Ajust described constitutes the equi ment located at the central or main station which serves tol transmit impulses lfrom the branch oiiice A to the line conducprises, amongv. vother parts, a continuous -ring 113 and an otter ring which-is divided into a plurality of segments 107 ,v 108, 109, 110, 111 and 112. Like the distributor vI a continuously revolving lbrush arm 102 carrying'brushes 103 and '104 is also provided.

- Connected to the smaller segments forming a part of the outer ring are the terminals of a set of condensers 115, 116, 117, 118 and 119 which serve in combination With a series of transfer relays 120, 121 and 114 and a set of storing relays 122, 123, 124, 125 and 126 to provide a complete overlap betweenA the selections received on the multiplex dis.

tributor M and those transmitted over the extension'circuit 8 by the start-stop distributor R. The Acondensers 115 to 119 inclu sive, are charged in accordancewith the apferation of the line relay 101 upon the passage of .the brush 104 overthe vcorresponding segments. V`Following the passage of the brush 104 over segment 111 and the engagement of this brush with the segment 105, anv energizing circuit is established. for the transfer relays 120, 121.,.and 114 which establish through their contactsa discharge circuit for the condensers including the,

relays. For bridging the outer ring of the` e distributor R with the inner ring 138, the distributor has a brush 130 carried by a brush arm 128 Which is normally held against rotation by a latch under the control of a release magnet .131. The release magnet 131 is controlled by relay 127, which in turn is energized in accordance with the energization of any one of the storing relays 122 to 126, inclusive. Thus, upon the energization of any one ofthese relays, an energizing circuit for relay 127 iscompleted thereby establishing an energizing circuit for the release magnet 131 .which permits the rotation of the brush arm 128.

The .receiving equipment at the branch of- \ice D comprises a receiving printer dia-` grammatically shown at 155 which .com-i prises the usual selecting` magnets 156, 157 158, 159 and 160 and the printing magnet 168. The respective magnets l'have their windings connected tothe segments 161, 162,

163e 164 and 165 forming a part of the outer ring of the distributor Q. The distributor Q, like the distributor G has a. brush arm 147 carrying a brush 148 which is arranged to bridge the segments forming a part of the outer ring with the segments 154, 166 and 152 for controlling the energization of the respective .ones of the selecting magnets depending upon the energization of relay 151 which is in turn controlled by the line relay 146 connected to the extension circuit 8.

Inasmuch as'v the apparatus.-associated with the other channel of the system is identical to the. equipment just described, further description thereof is considered unnecessary here. However, the rectangles des ignated by the characters S and T represent the e uipment intermediate the distributors (ur and I and H and R, respectively, which., as previously described, are shown diagrammatically for the sake of clarifying the drawings.

The operation of the'equipmentijust described is as follows: Assuming, for the sake of clearness, that the branch office `A desires mitter 24, contact 35 will be closed for causing the energization of. start relay 28, the energizingcircuit of which extends from control.

battery through the left-hand winding thereof, contact 35, segment 15, brush 13 and segment '14 of the transmitting distributor 10 to ground. The start relay 28 is thereupon energized and is locked up over a circuit under the control of the brush 13. Upon the energization ot the start relay 28, an energizing circuit is established for the release magnet 27 which, in operating, withdraws the release latch under its control from engagement with the brush arm 11, which is thereupon free to rotate whereupon the brush 12 consecutively completes circuits extending from the segments 18 to 22 inclusive, and the contacts ot the transmitter 24, which have been operated through the winding'of the pole changing relay 29. The pole changing relay 29 is energized upon the passage of the brush 12 over a segment to which one of the closed contacts of the transmitter 24 is connected for applying to the line 6 an impulse of a polarity corresponding to that normally applied thereto. However, the instant the brush 12 passes off the segment 23, an open circuit condition is established whereby the pole changing relay 29 reverses the position of its armature, connects the positive source of current with the apex of the ratio arms in which the receiving relay 36 is connected, but which does not respond to outgoing impulses. The receiving relay 37 located at the central office B does, however, respond to such changes in polarity and .reverses the position of its armature whereby the energizing circuit of the relay 38 is broken. Consequently, the energizing circuit for the release magnet 39 of distributor G is established. The release magnet 39 being energized, the brush arm 41 is thereby releasedfor rotation owing to the withdrawal of the release latch under its Contact 3() of the transmitter 24 being closed, an energizing circuit for the pole changing rel'ay 29 is established upon the passage of the brush 12 over segment 18 of the transmitting distributor 10, thus connecting the negative pole of the battery with the line conductor 6, and consequently, causing the reversal of the armature of the receiving relay 37 to the position shown in the drawing, which in turn, causes the energization of rela-v 38. The closure of the t'ront contact of relay 38 establishes upon the passage of the brush 42 over segment 47, an energizing circuit for relay-56 extending from battery through the armature and alternate contact of relay 38, segment 45, brush 42, segment 47 of the distributor G, and the winding of relay 56, and the contact and armature of relay 62 to ground. Upon the closure of the right-hand armature and ,contact of this relay, a locking circuit is established therefor, extending from battery through the left-hand contact and armature and winding thereof, and the contact and armature of relay 62 to ground. ontact 31 of the transmitter 24 being open, the pole changing relay 29 is caused to reverse the position of its armature upon the passage of the brush 12 over segment 19 to which contact 3l of the transmitter 24 is connected. Similarly, the receiving relay 37 at oliice B reverses the position 'of its armature, and consequently causes the deenergization of relay 38. Thus, upon the passage of the brush 42 over segment 48 of the distributor G, relay 57 will-not be energized. Contacts 32 and 34 of the transmitter 24 being closed, a condition similar to that described in connection withcontact 30 will be established for causing the energization of relays 58 and 60 in accordance with the energization of relay 38 upon the passage of the brush 42 over the segments to which these relays are connected. Relayv 59 will, however, not be energized owing to contact 33 of the transmitterubeing open so that an open circuit condition is established upon the passage of the brush 42 over the segment individual thereto.

Just prior to the completion of the cycle ofrotation of the brush arm 4l of the distributor G, an energizing circuit is established for relay (S1-extending from battery through segment 46, brush 42, segment 52 of the distributor G, winding of relay 61 and the contact and armature of rela 62 to ground. A locking circuit is established for relay 61 upon the closure of its left-hand contact extending from battery through the left-hand armature and contact and winding `of this relay, and the contact and armature of relay 62. Upon the closure of the right-y hand contact of rela 61, an energizing eircuit is conditioned tor relay 66,'but .which willl not be completed until relay 63 is energized, which, in turn, is under the control of relay 64 which is ot' the slow-to-operate type. The brush 88 of the multiplex distributor I in passing over segment 96 establishes an energizing circuit for clear out relay 75 which extends from battery through ring 98, brush 88, segment 96 of the distributor I and the winding of clear out relay 75 to ground. This relay, as previously described, controls the locking circuit of the' third group of storing relays 76 to 80, inclusive, so that upon the energization of this relay, any of these relays which might have previously been energized will be released and restore their armatures to the position shown in the drawing. Following the passage of the brush 88 ott' of segment 96` this brush engages segment 97 which establishes an energizing circuit for transfer relay 65 extending from battery through segment 98, brush 88, lsegment 97. armature and contact of relay 67. right-hand winding ot' relay 65 andthe right-hand armature and contact of relay 64 to ground. Relay 65 thereupon attracts its armatures and establishes through its left-hand larmature and contact a locking circuit for itself, while at its right-hand contact it establishes an energizing circuit for the third set of storing relays depending upon the energization of the relays of the second set. Should any of the relays of the second set be energized upon the energize.-

tion of relay 65, an energizing circuit forthe contact and armature of clear outA relay 75.

to ground. As previously described, upon the energization of the relays of the third set, a locking circuit is established therefor,

and they will be held energized until the energization of clear out relay 75 upon thel passage ofthe brush .88 over segment 96.

Relay in closing its left-hand contact also establishes an energizing circuit for relayl64 which, however, as previously described, Ais of the sloW-to-operate type and does not op-` erate during the period which the'relay 65 is transferring the impulses .stored in therelays to 74 from the second set of storing relays to the relays 76 to 80, forming the re lays ot the third set. However, upon the energization ot relay 64;,.the holding circuit of the relays of the second set is broken at its right-hand armature,l whereupon any of the relays of this set which happen to/be energized will be released, While at its left-'- hand contact an energizing circuit. is established orrelay 63 extending from battery,

armature and Contact of relay 64, Winding of relay 63, Winding ofvrelay 67 and the contact. and armature of relay 62 to ground. Relay 67 in energizing opens at its contact the initial energizing circuit of relay 65, thus preventing the energization .of this relay upon the subsequent passage of the brush 88 over segment 97 providing the impulses `have not been previously transferred to the re- `spective sets of storing relays. Relay 63H in closing its right-hand contacty establishes a locking circuit for itself While. at itsjlefthand contact an energizing circuit for relay 66 is established which conditions an ener-- gizing circuit for relay 62 and which is later completed upon the deenergiz'ation of relay' 64. Relay 66 also establishes an energizing circuit `for the relays of the second set of ster/ing relays corresponding to the relays of thlerst set which have been previously energized. The energizing ycircuit for the relaysjof the second set extends fromA battery through the right-hand armature and contact of relay 66, right-hand contact and armature of the relay 'energized' of the first set, right-hand Winding o the corresponding relay of the second set and the armature and contact of 4relay 64 which releases its armature upon the deenergization offrelay 65, which, in turn, is released upon the energization ol' relay 64. The impulses stored in the iii-st set of storing relays will t us be transferred 'to theisecond set of storing relays Which will be energized. in accordance therewith and lock up until subsequently released due to the energization of relay 64 as previously described. Upon the deenergization of relay 64, relay 62 is energized whereby the locking circuit of the -first set of storing relays 56 to 60 and that of relay 6l is open` for causingthe restoration of .these relays to normal so that the next succeeding group of impulses may be stored in `the storing relays 56 to 60 regardless of whether those stored vinthe other sets of lstoring relays have been cleared out.

set and which is later completed upon the energization of relay 65 under the control of the` synchronous multiplex distributor I. The relays` 57'and 59 not having been energized for the particular selection .chosen remain in the position shown in the drawing.

Consequently, the corresponding relays of v'the second andthird sets Will remain de energized. Relays 76" and 78 upon closingtheir right-'hand alternate contacts connects the positive pole of the battery with segments 94 and 92 of the distributor I, respectively, While relay 80 connects the negative pole of the battery with segment 90. Upon the passage of' the brush 89 of the multi leX` distributor I over the respective onesl o the segments to which the armatures of the relays of the third set are connected, a polarity of battery depending uponthe energization of the storing relays 76 to 8O will be applied to the apex of the ratio arms to which the receiving f relay 99 is connected, and` thence over the line conductor 7 to the central station C. The brush 89 in passing over segment 94 to which the armature of storing relay 76 is connected, an impulse of a positive polarity will be transmitted to the central station C Whichpasses through the armature of the receiving relay 101 for caus-` l ring 113, brush 104, segment 107 of the distributor M and the condenser 115 to ground. As the brush arm 87 continues to rotate conditions depending upon the position of the armatures of the storing relays 76 to 80 inclusive, will be set up for causing the corresponding positioning of the armature of receiving relay 101 at the central ofhce C. Thus, upon thepassage of the brush 104 over the segments to which the condensers 116, 117, 118 and. 119 areJ connected, these condensers will be charged depending upon the energization of the storing relays of the third set of storing relays located at the central office B. For the particular selection chosen, condensers 117 and 119 will be charged over vcircuits similar to that de-- scribed in connection with condenser 115. The brush 103 upon passing over segment 105 establishes an energizing' circuit for the transfer relays 120, 121 and; 114, the energizing circuit of which extends -from battery through the windings of these relays in series, segment 105, brush 103 and ring 106 to ground. These relays establish through their contacts a` discharge circuit for the condensers through the upper winding of the storing relays 122 to 126. Condensers 115, 117 and 119 having been charged, a discharge circuit therefor will be established upon the closure of the contacts of the transfer relay 120, 121 and 114 extending from the termina] of the condenser through the upper winding of the corresponding storing relays and the armature and contact of the transfer relay to the other terminal of the condenser. For

' the particular selection chosen relays 122,

124 and 126 will be energized which upon closing their lower armature and contacts establishes a locking circuit extendingy from batterythrough the armature, lower con tact and winding thereof, contact and arma- ,ture of relay 140 and the winding ot relay 127 to ground. Relay 127 is also energized over the circuit just traced.

Following the passage of the brush 88 over segment 90 of the multiplex distributor I, this brush engages segment 96 whereupon an energizing circuit is established for clear out relay'75 so that upon the energization of this relay the locking circuit for relays 76, 78 and 80 is broken thereby restoring these relays to the position shown in the drawing.

Should the brush 88 of the multiplex distributor I pass over segment97 prior to the passage of the brush 42 over segments 46 and 52 of the distributor G, the-completion of.

the energizing circuit of rela 63 will be prevented due to thelfact that'the relay 61 is at this time not energized. Thus, upon the continued rotation of the brush arm 87 no mutilation or piling up of the signals will be caused owing to the energization Qt the respective ones of the transfer relays for transferring the impulses from one set of storing relays to the next and nothing will occur except the transmission ot a blank signal over the line conductor 7, following the opening of the locking circuit of the relays forming the third set of storing relays. The transmission of a blank signal will have no ei'ect on the printing mechanism at the branch ofiice D.

Upon the energization of relay 127 an energizing circuit for the release magnet 131 is established extending from battery .throughthe contact and armature of this relay, winding of release magnet 131, segment 143, brush 129 and segment 141 to ground. Release magnet 131 upon being energized withdraws its release latch from engagement with the brush arm 129 thereby permitting the rotation thereof. The brush carried by the brush arm 139 consecutively connects the segments 132, 133, 134, 135 and 136 which are connected with the respective armatures of the vstoring relays 122 to 126 in circuit with the winding of the pole changing relay 142. Prior to the engagement of the brush 130 with the segment 132, and upon the passage of this brush off of segment 137, pole changing relay 142 is deenergized thereby impressing on the extension circuit'8 animpulse of a positive polarity which, upon being received at the branch ottice D, causes the reversal ofthe armature of receiving relay 146. Relay 146 in reversing the position of its armature causes the deene'rgization of relay 151` which, in turn, closes through its back contact an energizing circuit for release magnet 150 ot the distributor Q, thus releasing the brush arm 137 for rotation.

Upon the passage of the brush 130 over segment 132 aind owing to the fact that the storing relay 122 is energized for the particular selection chosen, an energizing cir cuit is established tor the pole changing` relay 142 extending trom battery through ring 138, brush 130, segment 132 ot' the distributor R, upper armature and contact of relay 122 and the winding of pole changing relay 142 to ground.

The closure 'ot 1 such a circuit causes lthe energization of the to this segment will be energized over a circuit extending from battery through thev winding of this magnet, segment 161, brush 148, ring 154 and the alternate contact and armature of relay 151 to ground. The

movement of the selecting bar under the control of this magnet'will be effected at this time. `lThe brush 129 in passing over segment 133 and inasmuch as storing relay 123. is deenergized causes t-he pole changing relay 142 to reverse the position of its armature and impress on the extension circuit 8 an impulse of a positive polarity. Similarly,.upon the passage of the brush 148 oversegment 162 to which the selecting magnet 157 is connected, an open circuit condition is established owing to the fact that the receiving relay 146 hasl reversed the position of its armature, and in turn caused the deenergization of relay 151. Conditions similar to that just described for selecting magnet 156 will be established upon the passage of the brush 148 over segments 163 and 165,' respectively, for causing the energization of thecorresponding selecting magnets 158 and 160 of the receiving printer 155. However, since the .storing relay 125 is not energized for this selection no eect'will be produced by the selecting magnet '159 upon the passage of the brush 148 over segment' 164 to which this selecting magnet is connected. 1 i

Following thel passage of the brush 148 oliE the segment 165 and the passage thereof over segments 168 and 167, a circuit is completed extending from battery through the` winding of printing magnet 168, segments 167, brush 148 and segment 166 to ground. Thus, the signals transmitted 'from the branch otiice A will be recorded on the receiving printer 155 at the branch office D over one channel of the iine conductor 7,"

equipped for duplex operation. I

Just prior to the completion of the cycle of lrotation by the brush arm 128, segment 139 is bridged with segment 141`by the brush 129 for causing the energization of clear out relay 140 which not only causes the dcenergization of relay 127 but alsoopens the locking circuit of 'the storing relays 122, 124 and 126 which thereupon deencrgize. Likewise, uponA the engagement ot the brush' 130 with the segment 137 an energizing circuit is established for the pole changing vrelay 142 which impresses upon the extension circuit 8, an impulse of a negalive polarityy for causing the relay 146 at the branch oiiceD to position its armature to that shown in the drawing thereby causing the energization of relay 151.'

It is apparent from the previous descrip- 'tion that the present invention -provides through the instrumentalities of means in-l termediate the distributor mechanisms at the central oiiices, a system lin which signaling' impulses are transmitted over the main line at .a speed. within predeternnned limits.

-lvhile they transmitting mechanism must necessarily be operated at aspeed '-Within such limits, on thel other hand vthe receiving mechanism associated with' the extension circuit at the distant station is onerated at a speed in excess of the Spee at which signals are transmitted over the main line. K Although the invention has been illust-rated in connection with a system where code combinations of message 'impulses originating at a branch office are transferred Ito a main or central oiiice at which synchronous printing telegraph apparatus is located and thence over a conductor equipped for duplex. operation to the secondcentrall or main station having equipmentsimilar to that lrst referred to from which 1t 1s transferredlover anvextension circult'to a distant circuit, itis, of course, obvious that the invention-may lne/readily applied to other types ofy system withoutI departing from the spirit and scope of the invention.

What is claimedis: A1. A telegraph system comprising a, main line,y a plurality of branch lines, means interc'onnecting sai-d mainv and branch lines, transmitting and receiving mechanisms associated with said branch lines, means for transmitting impulses over said mainline at a speed Within predetermined lii'nits, means for controlling 'the operation of the transmitting mechanism independently 'of thejreceiving mechanism at a speed Within such'predetermined llmits, and means for A- operating said recelving mechanlsm at a' speed slightly in excess .of the maximum limit at which signals are transmitted vover .the .main line.

2. A telegraph system comprising a main line, 'a plurality of branch lines, means interconnecting said main and branch lines,

' located at each of said central stations, cx-

tensionA circuits extending from said centra-l stations, intermittently operable apparatus associated with each of said extension circuits, and means for operating said intermittently operable yapparatus independently of'saidmultiplex apparatus.

4; In combination, a plurality of central stations connected by a line conductor, synchronous multiplex apparatusl located at said central stations and connected to said line conductor, a plurality of branch offices inter-connected with said central stations by extension circuits, intermittently operable apparatus associated with said extension circuits and located at said central stations, means Jfor controlling the operation of said intermittently operable apparatus independently ofsaid synchronous multiplex apparatus and means associated with the apparatus at the centralstations `for providing a complete overlap between the selections received Jfrom an extension circuit and those transmitted to the main line and between the selections received from the main line which are subsequently transmitted over an extension circuit.

5g In combination, a plurality of central stations connected by a line conductor, synchronous multiplex apparatus located at said central stations and connected tosaid line conductor, a. plurality of branch offices interconnected with said central stations by extension circuits, intermittently operable distributing mechanism associated with said extension circuits and located at the central stations, means for controlling the operation of said intermittently operable apparatus independently of said synchronous multiplex apparatus, means intermediate the intermittently operable distributing mechanism and the multiplex apparatus for providing a complete overlap between the selections received on the intermittently operable distributing mechanism and those transmitted by the multiplex apparatus, and means intermediate the multiplex apparatus and the intermittently operable distributing mechanisms located at the other-station for providing a complete overlap between the selections received on the multiplex apparavtus and those transmitted to the extension tension circuits, intermittently operable distributing mechanism associated with said extension circuits and locatedgat the central stations, means at each of the central stations connected intermediate the intermittently operable distributing mechanism and ,the multiplex apparatus for providing a complete overlap between the selections received on the intermittently operable dis'- tributing mechanism and those transmitted b v the multiplex apparatus comprising a plurality of groups of storing relays under the joint'control of t-he intermittently operable distributing mechanism and the multiplex apparatus, and a series of electrostatic means and a group of storing relays at the other station for providing a complete overlap between the selections received on the multiplex apparatus and those transmitted ently of such synchronous multiplex apparatus and means intermediate said multiplex f and intermittently operable apparat-us for providing a complete overlap between the selections received from said multiplex apparatus and those transmitted by said intermittently operable apparatus.

8. In combination, a line conductor, synchronous multiplex apparatus connected thereto, an extension circuit, intermittently operable apparatus connected to said extension circuit, and means comprising a group of electrostatic means and a set of relays for providing a complete overlap between the selections received from the multiplex apparatus and those transmitted by said intermittently operable apparatus.

9. In combination, a main line, synchronous multiplex apparatus connected thereto, intermittently operable` distributing mechanism associated with said multiplex apparatus, means comprising a group of electrostatic means and a set of relays for providingva complete overlap between the selections received on the multiplex apparatus and those transmitted by the intermittently operable distributing mechanism, and means controlled by said multiplex apparatus for transferring the effects of said electrostatic means to said relays.

10. In combination, a main line, synchronous multiplex apparatus connected thereto,

intermittently operable distributing mechanism associated with said multiplex apparatus, and means comprising a group oi condensers and a set of relays for providing a complete overlap between the selections received on the multiplex apparatus and those transmitted bythe intermittently operable distributing mechanism, and a group of relays controlled by said multiplex apparatus for establishing a discharge circuit tor said condensers to said set of storing relays whereby said relays are energized in accordance with the condensers which have previously been charged.

11. In combination, a line conductor, synchronous multiplex apparatus connected thereto, an extension circuit, start-stop distributing mechanism associated with said extension circuit, means intermediate said multiplex apparatus and said start-stop distribi ISO uting mechanism comprising a, group of condensers and a set of relaysU for providing a complete overlap between the selections rcceived on the said multiplex apparatus and those transmitted by said start-stop distrib,-`

uting mechanism, :incl means operated upon the energlzation of any one of Smd relays for causing the releaselof sid start-stop clis-h In Witness whereof, I hereunto subscribe l0 my name this 30th vday of December A. D., 1921.

ERWIN P. BANCROFT. 

